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The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them. Dan/Panther

unbeldi

This is a field trial telephone that was used in the Morris trial for the first large-scale stored program control electronic switching system. The experience from the Morris system led directly to the development of the NO. 1-ESS.

The switching circuits in the Morris system used cold-cathode gas-filled tubes and required low current devices. The ringing signals needed to pass through the same tubes as the voice signals, but the standard ringing voltage was too high for that. So they used a low-voltage audio frequency for ringing and the subscriber set had a transistor circuit that detected this frequency and amplified it for alerting through the horn, as you see in this picture.

These sets dialed at 20 pulses/s.

This is a very attractive set, not only technically, but also by the color and condition. Outstanding !

unbeldi

The details of the Morris system are rather interesting and funny in a way. For example, to keep the gas-filled electron tube diodes firing better, they installed fluorescent lights in the cabinets, making the whole switching system glow ominously--and they probably saved on light fixtures in the switch room.

Because of using audio frequencies for ringing, it was rather easy to provide fully selective ringing on party lines for up to eight subscribers by simply tuning the ring detector in the telephones to the appropriate frequency. No specially made ringers were needed for each party.

The system provided the first version of vertical customer features to the subscribers, such as short code dialing with two digits, and call forwarding.

Interesting that the cover has two mouse-holes for the handset cord. Notice the revised placement of where the handset cord exits the phone. A new mouse-hole for that plus the one in he normal position. That tells me that the vent-slots for the ringer and the new mouse-hole were all cut into a production cover, which makes perfect sense for a limited production prototype.

The base, however is custom, at least not your average 500 base. It seems they did put the little slit in the side in the normal handset cord position.

« Last Edit: October 01, 2014, 07:50:39 PM by Phonesrfun »

Logged

-Bill G

unbeldi

Interesting that the cover has two mouse-holes for the handset cord. Notice the revised placement of where the handset cord exits the phone. A new mouse-hole for that plus the one in he normal position. That tells me that the vent-slots for the ringer and the new mouse-hole were all cut into a production cover, which makes perfect sense for a limited production prototype.

That is probably correct. You can tell that the hole was cut, because it doesn't have the little rim around it as does the original one.

When you look at the seller's high resolution pictures of the inside housing, one can see the cut marks on the slots, and the fact that several ribs have been cut out too. The housing is a standard production housing with the normal manufacturing mold stamp (C|60).

I dont know how the experiment was done at Morris but AE Canada tested their very first electronic CO, the "C1" (and yes, everything that I have been told does indicate that "C1" means Canada's First electronic exchange) at an existing CO on the outskirts of Vancouver in an area known as Whonnock.

This was a few years later in mid to late 1960's, maybe 1967 and special phones were not required by then. During the test which went on for somewhere between one and two years, the existing SxS CO and the new C1 CO were cut back and forth several times. At the conclusion the C1 exchange was removed and sent back to AE in Brockville for further examination.

I would expect that a similar situation existed at Morris. They would not likely have cut this CO in and removed the old one as in a normal CO cutover. They quite likely cut back to the old CO some time after the experiment concluded though maybe others have more information.

I would expect that these special phones that were required for the new CO would have been made to work with the existing CO as well if at all possible. So thinking out loud about the lamp...could it be a resistance lamp in the ringer circuit to possibly make the phone compatible with the existing CO at Morris as well as new test CO? Cutting a CO over quickly is one thing but having to replace all phones simultaneously is another! Making the new phones compatible with both Exchanges would solve a lot of "logistics" problems.

They couldn't install these new phones in the subscribers house until after the CO cut over to the new electronic exchange if the existing CO ringing would damage these phones. That would leave the customer out of service for some time or at least unable to receive calls until the phone was switched out.

I dont know how the experiment was done at Morris but GTE Canada tested their very first electronic CO, the "C1" (and yes, everything that I have been told does indicate that "C1" means Canada's First electronic exchange) at an existing CO on the outskirts of Vancouver in an area known as Whonnock.

This was a few years later in mid to late 1960's, maybe 1967 and special phones were not required by then. During the test which went on for somewhere between one and two years, the existing SxS CO and the new C1 CO were cut back and forth several times. At the conclusion the C1 exchange was removed and sent back to GTE in Brockville for further examination.

I would expect that a similar situation existed at Morris. They would not likely have cut this CO in and removed the old one as in a normal CO cutover. They quite likely cut back to the old CO some time after the experiment concluded though maybe others have more information.

I would expect that these special phones that were required for the new CO would have been made to work with the existing CO as well if at all possible. So thinking out loud about the lamp...could it be a resistance lamp in the ringer circuit to possibly make the phone compatible with the existing CO at Morris as well as new test CO? Cutting a CO over quickly is one thing but having to replace all phones simultaneously is another! Making the new phones compatible with both Exchanges would solve a lot of timing problems.

Terry

It is rather improbably that these were meant to be compatible. These are rather different sets, and although they used the same handset elements, the circuitry was very different, using low current transistor-based transmission circuits. The dial also is not compatible as it was pulsing at 20 PPS, not 10.

However, the lamp could still be some kind of resistance element, or perhaps a circuit protector the guard against high currents.

Morris was to be converted from manual service to dial in 1959 with a 5XB switch. The ESS was installed in parallel to the crossbar, but the crossbar was finished before the ESS. The ESS was a completely self-sufficient operation however and there was no failover in case of trouble. Turns out that after a few months, the trouble reports from customers were lower than from the XB.